package javajc;

import java.util.Scanner;

public class day04 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int score = scan.nextInt();
        System.out.println("请输入成绩");
        if(score<0 || score>100){
            System.out.println("成绩不合法");
        }else if(score>=90){
            System.out.println("A");
        }else if(score>=80){
            System.out.println("B");
        }else if(score>=60){
            System.out.println("C");
        }else {
            System.out.println("D");
        }
    }
}
